Version 8 or higher
The only containing text expression type that doesn't remove the CR or LF characters is the Multi-line RegEx. If you choose that option you should be able to search for CR, LF, e.g.
Containing Text: ABC\n
would match to ABC with a LF but not ABC with CR LF.
Previous answer (ie earlier versions)
FileLocator Pro does not pass the raw text to the regex engine. The text files are loaded and valid EOL characters are replaced with \r\n, invalid EOL characters are removed.
This occurs at quite a low level in the file processing process. You could write a COM component to replace the file reading process with your own. You'd need to implement
IExtDataInterpreter which has three methods:
HRESULT Open([in] BSTR bstrPathName);
HRESULT GetNextLine([out] BSTR* pbstrText, [out] LONG* pnLine);
The text from GetNextLine is passed directly to the search engine without any further processing. If you'd like more information please contact Tech Support.
Another option would be to write a Custom Extension that converts the lone \n into something above the 0x1f range for searching.